Busiest California Highways, based on Average
Daily Traffic

/I-110/CA 110:
286,000I-110 runs from the Port of Los Angeles to
downtown Los Angeles. Route 110 runs from downtown LA to Pasadena. The first
freeway in California.

2.

I-405: 325,000.I-405 runs from southern Orange County (near Irvine) to the
northern San Fernando Valley, in Los Angeles.

7.

Route 91: 271,000.Route 91 runs from the beach communities such as Redondo Beach
through Orange County to Riverside.

3.

US 101:
308,000.US 101 runs from downtown Los Angeles, through
Ventura, Santa Barbara, San Luis Obispo, Monterey, San Jose, San Francisco,
Marin, and Redwood Country. It is freeway in Southern California, and the
greater San Jose/San Francisco area.

8.

I-8: 258,000.I-8 runs from the Arizona border at the southern end of the state to
San Diego.

4.

I-5: 299,000.I-5 is the backbone of California, running from Mexico to the Oregon
border. Major urban areas traversed include San Diego, Los Angeles, and
Sacramento.

9.

I-210: 256,000.I-210 runs along the northern foothills of Los Angeles, from near the
I-5/I-405 junction, through Pasadena, on to Pomona. It will eventually run to
San Bernadino when the Route 30 freeway is completed and renumbered as part of
I-210.

5.

I-580: 286,000.I-580 runs from Vernalis to Oakland, through Livermore. It is a main
connector between I-5 and the San Francisco area.

10.

I-80: 250,000I-80 is the major northern E/W freeway, running from the Nevada
border to San Francisco, through Sacramento.

Route 229: 100-500.This routing has been deleted; in 1992, in ran from Route 58 near
Santa Margarita to Route 41 near Creston.

10.

Route 271: 90-980.This is a former segment of US 101; it runs from Cummings to the
Humboldt-Mendocino county line.

Most Variable Traffic

The highways listed below have the greatest percentage variance in their
ADT, as of 1993:

1.

Route 2: 310 to
130,000 vehicles/day, for a growth of 41,834.5%Route 2
runs from Santa Monica to Route 138. It includes major city streets (Santa
Monica Blvd), freeways (Glendale Freeway), and a highway through the mountains
(Angeles Crest Highway)

6.

Route 299: 150 to
44,500 vehicles/day, for a growth of 29,565.7% Route 299
(former US 299) runs in far northern California, from US 101 to the Nevada
state line. I don't know where the low and high traffic points
are.

2.

Route 39: 150 to 61,000
vehicles/day, for a growth of 40,565.7%Route 39 runs
from Huntington Beach through San Gabriel Canyon. It includes major city
streets as well as a pass over the mountain.

7.

Route 41: 460 to 112,000
vehicles/day, for a growth of 24,246.8%Route 41 runs
from Route 1 to Yosemite National Park. It is a major freeway in Fresno; the
low is probably is either in the section from Shandon to Atascadero or from
Atascadero to Morro Bay. These sections are little-used, winding country roads.

3.

Route 168: 200 to 79,000
vehicles/day, for a growth of 39,399.0% Route 168 runs
from Fresno to Route 266 near the Nevada border. The high traffic is in Fresno;
the low across the Sierras.

Route 4: 240 to 91,000
vehicles/day, for a growth of 37,815.7% Route 4 runs
from I-80 to Route 89 near Markleville. The high traffic is in the segment from
I-80 to Stockton; the low in Gold Country.

9.

Route 58: 290 to 63,000
vehicles/day, for a growth of 21,623.1% Route 58 runs
from US 101 to I-15/I-40. The segment between Barstow and Bakersfield is a
major trucking route.

5.

Route 178: 180 to 58,000
vehicles/day, for a growth of 32,121.2% Route 178 runs
from Bakersfield to Freeman via Walker Pass. The high traffic is in
Bakersfield; the low is likely over the pass or in the high
desert.

10.

Route 94: 800 to 172,000
vehicles/day, for a growth of 21,399.0% Route 94 runs
between I-5 and I-8 in San Diego. This is the ML King and Campo Freeways. I
have no explanation for the low number.

Most Constant Traffic

The highways listed below have the least percentage variance in their
ADT, as of 1993. Highways with no traffic are excluded, as are highways for
which my source documented provided only a single number.

I-380: 113,000 to
131,000 vehicles/day, for a growth of 14.9% I-380 runs
from Route 1 near Pacifica to the San Francisco International Airport, but the
segment from Route 1 to I-280 is unconstructed.

2.

Route 167: 360 to 410
vehicles/day, for a growth of 12.9% Route 167 runs from
US 395 north of Mono Lake to the Nevada state line in the vicinity of the Pole
Line Road. A road with constant low traffic.

6.

Route 219: 12,200 to 14,300
vehicles/day, for a growth of 16.2% Route 219 runs from
Route 99 at Salida easterly to Route 108.

3.

Route 77: 15,000 to 17,000
vehicles/day, for a growth of 13.0% Route 77 runs from
I-880 near 42nd Avenue to Route 24 near Lafayette.

7.

Route 197: 1,600 to 1,950
vehicles/day, for a growth of 20.9% Route 197 runs from
Route 199 to Route 101 staying north of the Smith River.

I-205: 57,000 to 65,000
vehicles/day, for a growth of 13.0% I-205 runs from
I-580 west of Tracy to I-5 east of Tracy.

8.

Route 282: 14,100 to 18,000
vehicles/day, for a growth of 26.7%Route 282 runs from
Route 75 to the Naval Air Station at North Island in Coronado in San
Diego.

4.

Route 200: 1,650 to 1,900
vehicles/day, for a growth of 14.2% Route 200 runs from
US 101 to Route 299 staying north of the Mad River.

I-980: 148,000 to 189,000
vehicles/day, for a growth of 26.7%The "John B Williams"
freeway, running from I-880 to I-580 in Oakland.

Most Busiest Route, on average,
per Mile, at the time of Most Traffic

The highways listed below have the highest high average daily traffic
per mile of the route, as of 1993:

1.

I-980: 148,000 to
189,000 vehicles/day over 2 miles, gives a "per mile" ADT of 74,000 to 94,500
vehicles per day per mile.The "John B Williams" freeway,
running from I-880 to I-580 in Oakland. Short and busy; a winning combination
in this list.

6.

I-380: 113,000 to
131,000 vehicles/dayover 3 constructed miles, gives a "per mile" ADT of
37,666.6 to 43,666.6 vehicles per day per mile.I-380
runs from Route 1 near Pacifica to the San Francisco International Airport. A
short busy route to a large busy airport.

2.

Route 259: 55,000 to 66,000
vehicles/day over 1 mile.Route 259 is basically a ramp
between I-215 and Route 30 (future I-210) in San Bernadino. Another short but
busy route.

7.

Route 77: 15,000 to 17,000
vehicles/day over 0.4 constructed miles, gives a "per mile" ADT of 37,500 to
42,500 vehicles per day per mile.Route 77 runs from
I-880 near 42nd Avenue to Route 24 near Lafayette. It serves as an on-ramp to a
major freeway in the area.

3.

Route 262: 45,000 to 61,000
vehicles/day over 1 mile.Route 262 runs from I-880 to
I-680 near Warm Springs. Another short route connecting
freeways.

8.

Route 260: 25,000 to 60,000
vehicles/day over 2 constructed miles, gives a "per mile" ADT of 12,500 to
30,000 vehicles per day per mile.Route 260 runs from
Route 61 in Alameda to I-880 in Oakland, including the tubes between the
Oakland and Alameda. This is actually signed as part of Route 61.

4.

Route 125: 71,000 to 91,000
vehicles/day over the 2 constructed miles of this route, gives a "per mile" ADT
of 35,500 to 45,500 vehicles per day per mile.Route 125
is a route actually under construction in San Diego; it runs from Route 905 to
Route 56. The constructed portion carries a lot of border
traffic.

Route 282: 14,100 to 18,000
vehicles/day over 0.6 constructed miles, gives a "per mile" ADT of 23,500 to
30,000 vehicles per day per mile.Route 282 runs from Route 75 to the Naval Air Station at North Island in Coronado in San
Diego.

5.

Route 114: 44,000 vehicles/day
over 1 mile.Route 114 is a short route from US 101
(although at the time of statistics, it was from I-280) to Route 84 near Palo
Alto, near the Dumbarton Bridge.

10.

Route 242: 54,000 to 88,000
vehicles/day over 3 constructed miles, gives a "per mile" ADT of 18,000 to
29,333.33 vehicles per day per mile.Route 242 runs from
I-680 to Route 4 north of Concord. It is a former part of Route 24.

Least Busiest Route, on average,
per Mile at the time of most traffic

On the other end of the spectrum, the routes with the lowest high ADT
per mile are:

1.

Route 266: 70-110 over
12 miles, gives a "per mile" ADT of 5.8 to 9.2 vehicles per day per
mile.Route 266 is a 12-mile route in eastern Mono
county, providing a short loop near Oasis.

6.

Route 172: 110-270
over 9 miles, gives a "per mile" ADT of 12.2 to 30.0 vehicles per day per
mile.Route 172 runs from Route 36 at Mineral to Route 36
near Morgan Summit. It was originally part of Route 36.

2.

Route 167: 360-410 over 21 miles,
gives a "per
mile" ADT of 17.1 to 19.5 vehicles per day per mile.Route 167 runs from Mono Lake to the Nevada state line in Mono
County.

7.

Route 270: 350 over 10 miles,
gives a "per mile" ADT of 35 vehicles per day per mile.Route 270 is the way to Bodie State Historic Park from US 395 in Mono
County. #3 on the least busy routes list.

3.

Route 96: 500-3,800 over 147
miles, gives a "per mile" ADT of 3.4 to 25.9 vehicles per day per
mile.Route 96 runs from Route 299 near Willow Creek to
I-5.

8.

Route 254: 540-1,200 over 32
miles, gives a "per mile" ADT of 16.9 to 37.5 vehicles per day per
mile.Route 254 is a former portion of the Redwood
Highway that connects a a number of state park units near US 101 in Redwood
country.

4.

Route 136: 200-500 over 18 miles,
gives a "per
mile" ADT of 11.1 to 27.8 vehicles per day per mile.Route 136 runs from US 395 near Lone Pine to Route 190 via
Keeler.

9.

US 95: 1,500-5,400
over 117 miles, gives a "per mile" ADT of 12.8 to 46.2 vehicles per day per
mile.US 95 runs from I-10 near Blythe to the Nevada
state line.

5.

US 395: 1,050-16,600
over 557 miles, gives a "per mile" ADT of 1.9 to 29.8 vehicles per day per
mile.US 395 runs from north of San Bernardino to the
Oregon border, with a break when it passes through Nevada. The first long route
in this category.

10.

Route 127: 380-4,700 over 91
miles, gives a "per mile" ADT of 4.17 to 51.6 vehicles per day per
mile.Route 127 runs from I-15 near Baker to the Nevada
state line via the vicinity of Death Valley Junction. Another high desert
routing.

Most Busiest Route, on average, per
Mile at the time of Least traffic

The highways listed below have the highest low average daily traffic per
mile of the route, as of 1993:

1.

I-980: 148,000 to
189,000 vehicles/day over 2 miles, gives a "per mile" ADT of 74,000 to 94,500
vehicles per day per mile.The "John B Williams" freeway,
running from I-880 to I-580 in Oakland. Short and busy; a winning combination
in this list. Also #1 when most busiest.

6.

Route 77: 15,000 to
17,000 vehicles/day over 0.4 constructed miles, gives a "per mile" ADT of
37,500 to 42,500 vehicles per day per mile.Route 77 runs
from I-880 near 42nd Avenue to Route 24 near Lafayette. It serves as an on-ramp
to a major freeway in the area. #8 when most busiest.

2.

Route 259: 55,000 to 66,000
vehicles/day over 1 mile.Route 259 is basically a ramp
between I-215 and Route 30 (future I-210) in San Bernadino. Another short but
busy route. Also #2 when most busiest.

7.

Route 125: 71,000 to 91,000
vehicles/day over the 2 constructed miles of this route, gives a "per mile" ADT
of 35,500 to 45,500 vehicles per day per mile.Route 125
is a route actually under construction in San Diego; it runs from Route 905 to
Route 56. #4 when most busiest.

3.

Route 262: 45,000 to 61,000
vehicles/day over 1 mile.Route 262, which is soon to be
deleted, runs from I-880 to I-680 near Warm Springs. Another short route
connecting freeways. Also #3 when most busiest.

8.

Route 282: 14,100 to 18,000
vehicles/day over 0.6 constructed miles, gives a "per mile" ADT of 23,500 to
30,000 vehicles per day per mile.Route 282 runs from Route 75 to the Naval Air Station at North Island in Coronado in San Diego. Tied for
#8 when most busiest.

4.

Route 114: 44,000 vehicles/day
over 1 mile.Route 114 is a short route from I-280 to
Route 84 near Palo Alto, near the Dumbarton Bridge. Moves up from #5 when most
busiest.

9.

Route 109: 20,700 vehicles/day
over 1 constructed mileRoute 109 runs from Route 84 to US 101. The only route on this list not also on the most busiest/mile
list.

5.

I-380: 113,000 to 131,000
vehicles/dayover 3 constructed miles, gives a "per mile" ADT of 37,666.6 to
43,666.6 vehicles per day per mile.I-380 runs from Route 1 near Pacifica to the San Francisco International Airport. A short busy route
to a large busy airport. #6 when most busiest.

10.

Route 242: 54,000 to 88,000
vehicles/day over 3 constructed miles, gives a "per mile" ADT of 18,000 to
29,333.33 vehicles per day per mile.Route 242 runs from
I-680 to Route 4 north of Concord. It is a former part of Route 24. Also #10
when most busiest.

Least Busiest Route, on average, per
Mile at the time of Least traffic

The highways listed below have the lowest low average daily traffic per
mile of the route, as of 1993:

1.

Route 299: 150-44,500
vehicles/day over 307 miles, gives a "per mile" ADT of 0.5 to 145.0 vehicles
per day per mile.Route 299 (former US 299) runs in far
northern California, from US 101 to the Nevada state line.

6.

Route 1: 750-97,000
vehicles/day over 656 miles, gives a "per mile" ADT of 1.14 to 147.9 vehicles
per day per mile.Route 1 runs from southern Orange
County to US 101 near Leggett. The coast highway.

2.

Route 36: 180-26,500 vehicles/day
over 250 constructed miles, gives a "per mile" ADT of 0.72 to 106 vehicles per
day per mile.Route 36 runs from US 101 to US 395 in far
Northern California.

Route 3: 140-12,500 over 146
miles, gives a "per mile" ADT of 0.96 to 85.6 vehicles per day per
mile.Route 3 runs from Route 36 near Peanut to
Montague.

8.

Route 58: 290-63,000 vehicles/day
over 241 miles, gives a "per mile" ADT of 1.20 to 261.4 vehicles per day per
mile. Route 58 runs from US 101 to I-15/I-40.

4.

Route 33: 300-37,500 over 290
miles, gives a "per mile" ADT of 1.03 to 129.3 vehicles per day per
mile.Route 33 runs from Ventura in various segments up
to I-5 near Vernalis.

9.

Route 4: 240-91,000 vehicles/day
over 192 miles, gives a "per mile" ADT of 1.25 to 473.6 vehicles per day per
mile. Route 4 runs from I-80 to Route 89 near
Markleville.

5.

Route 190: 200-14,800 over 188
constructed miles, gives a "per mile" ADT of 1.06 to 78.7 vehicles per day per
mile.Route 190 runs through Death Valley, from US 99
near Tipton to Route 127 near Death Valley Junction.

10.

Route 49: 400-43,000 vehicles/day
over 295 miles, gives a "per mile" ADT of 1.36 to 145.8 vehicles per day per
mile.Route 49 is primarily the Gold Country highway. It
runs from Route 41 near Oakhurst to Route 70 near Vinton through the Sierra
gold country.